Russia unleashes 'massive' airstrike on Ukraine, Zelenskyy says

KYIV and LONDON -- Russian missiles struck Kyiv early on Wednesday, killing at least four, destroying homes and temporarily knocking out power for many, Ukrainian officials said.

"Another massive Russian air attack against our country," President Volodymyr Zelenskyy said on social media. "Six regions came under enemy fire."

At least 20 Iranian-made Shahed drones and 44 missiles were fired, the Ukrainian Defense Ministry said in a statement.

Fifteen of the uncrewed drones were intercepted, along with at least 29 cruise missiles of varying types, Ukraine said.

"We are grateful to our brave air defenders and our international partners who help us strengthening air defense capabilities," the ministry said.

The air raid alert began at about 6 a.m. local time and lasted for about three hours.

At least three people were killed and another 16 were injured in Kyiv, according to the city administration. Another person was killed by the strike in Mykolaiv, where dozens of houses were hit, Zelenskyy said. Another two were injured in Kharkiv, he said.

"My condolences to all who have lost loved ones," he said. "We will definitely retaliate against Russia; terrorists will always face the consequences of their actions."

U.S. Ambassador to Ukraine Bridget A. Brink said, who is in Kyiv, said she and others around the country awoke to "another massive Russian missile and drone attack."

"There is no time to lose," she said on social media. "Ukraine needs our security assistance now."

ABC News' Joe Simonetti contributed to this story.